How can I display comments only in a particular category?

Right now in the category archive page I am using:
CODE
<MTComments lastn="7">
    <$MTCommentBody convert_breaks="1"$>
    <p class="info"><MTCommentEntry><a href="<$MTEntryLink$>"><$MTEntryTitle$></a></MTCommentEntry> |
    Posted by <$MTCommentAuthorLink spam_protect="1"$> on <$MTCommentDate$>.</p>
    </MTComments>


This displays the last 7 comments in the whole blog, not in the category. Also, how I want to display the number of comments in a category (on the category archive page).